Assessment of airway inflammation in asthmatic children by measuring nitric oxide derivatives in induced sputum versus blood

Nitric oxide [NO] plays an important role in inflammation involving the airways. In this study, the concentration of NO metabolites, nitrite and nitrate, were measured in induced sputum and compared with serum in 18 children with bronchial asthma and 10 normal children. The study was done on the asthmatic children attending the outpatient clinics of the Pediatric and Chest Departments of Tanta University Hospital. Asthmatic children had ages ranging from 10-15 years. They had significantly higher NO metabolites than control subjects, in induced sputum [1082.44 +/- 86.72 micro mol/l vs. 552.00 +/- 37.34 micro mol/l, P<0.01] but not in serum. The area under the curve [AUC] revealed that the level of NO metabolites in induced sputum [0.78] was more sensitive and specific than the determination of serum NO metabolites [0.53] in differentiation of children with asthma from control subjects. In induced sputum, IL-5 was detected more frequently in children with asthma than in control subjects [15/18 [83%] vs. 1/10 [10%], [P<0.01]]. Asthmatic children had a significantly higher eosinophilic cationic protein [ECP] concentration in induced sputum compared with controls [617.89 +/- 172.78 ng/ml vs. 155.50 +/- 30.31 ng/ml, P<0.01], Serum ECP levels reached significantly higher levels in asthmatic children [691.15 +/- 71.31 ng/ml] than in controls [114.20 +/- 18.45 ng/ml] [P<0.01]. In induced sputum, eosinophils and neutrophils were significantly higher in asthmatics than controls [eosinophils: 32.50 +/- 6.69% vs. 1.9 +/- 0.22%, P<0.01; neutrophils: 17.5 +/- 2.5% vs. 8.4 +/- 1.6%, P<0.01], whereas the proportion of macrophages was lower in asthmatics [24.9 +/- 6.1% vs. 85.0 +/- 1.5%, P<0.01]. The level of NO metabolites in induced sputum showed significant negative correlation with the degree of airflow obstruction [FEV[1] /FVC%]; [r=-0.73, P=0.001] and positive correlation with ECP in induced sputum [r=0.61, P=0.007]. Nitric Oxide [NO] metabolites in induced sputum positively correlated with the percentage of eosinophils in sputum [r=0.62, P=0.006]. The percentages of shedded epithelial cells in sputum, used to express NO-related cellular toxicity, significantly correlated with the concentration of NO derivatives in induced sputum [r=0.71, P<0.01]. No significant correlation was found between the degree of bronchial hyperreactivity to methacholine and the level of NO metabolites in induced sputum. From this study, it can be concluded that measuring NO metabolites levels in induced sputum is a more valuable marker to assess allergic inflammation of the airways in asthmatic children than measuring NO metabolites in serum

Urinary leukotriene E[4] in asthmatic children with and without nocturnal exacerbations

Nocturnal exacerbations of bronchial asthma are very common and disturbing signs with serious consequences on patient's quality of life. The exact mechanism of these exacerbations is not known but inflammatory mediators may play an important role. To study the role of leukotriene E[4] [LTE[4]] in the pathogenesis of nocturnal exacerbations of bronchial asthma. The study was conducted on 50 asthmatic children who used to attend the outpatient clinics of the Pediatric and Chest Departments of Tanta University Hospital. Their ages ranged 8-14 years. The study was carried out over 10 months from October 1, 2000 to July 31, 2001. They were classified into two groups. Group A included 25 asthmatic children without nocturnal symptoms, and group B comprised 25 children who used to have nocturnal asthma exacerbations. Twenty non-asthmatic children of comparable ages were included in the study as controls. All of the children were subjected to full history taking, clinical examination, pulmonary function tests [PFTs], methacholine bronchial challenge test, and measurement of LTE[4] in urine. Values of morning drop of peak expiratory flow [PEFR] in children with nocturnal symptoms [Group B] was significantly higher than those in the asthmatic children without nocturnal exacerbations [Group A] [P<0.05]. The PC[20] FEV[1] was significantly lower in group B than in group A [P<0.05]. Urinary LTE4 levels were found to be significantly higher in group B than in group A [P<0.05]. In asthmatic children with nocturnal exacerbations [group B], urinary LTE[4] levels were found significantly higher at night more than at day hours [P<0.05]. Also, in this same group B, there were significant positive correlations between urinary LTE[4] levels and morning drop in PEFR values and significant negative correlation between urinary LTE[4] levels and PC[20] FEV[1] [P<0.05]. There was no significant difference in urinary LTE[4] levels between atopic and non-atopic asthmatic children. Measurement of urinary LTE[4] levels may represent a non-invasive method for assessment of airway inflammation and for predicting the outcome of nocturnal exacerbations that disturb the life of asthmatic children